1. Field of the Invention
The invention relates to an electric press, and more particularly relates to an electric press provided with a device for preventing the electric press from generating dusts in a room where the electric press is located while the electric press is operated. The electric press is relatively simple in structure and is adapted to being used in a clean space factory and/or a product studying and researching room where the space is made clean.
2. Prior Art
So far, there has not been proposed an electric press provided with a device for preventing the electric press from generating dusts in a room where the electric press is located while the electric press is operated.
It is admitted that some industrial robots have been provided with a dust generation preventing device. However, such dust generation preventing device has been generally lacked in adaptation to the customer""s requirements.
Now a clean electric press is demanded, which will not produce dusts in a room where the press is used. Such an electric press is required to have an optimum exhaust power which will produce an exhaust flow matching the amount of dusts generated in the electric press.
In case the electric press is provided with an exhaust port of large diameter, an exhauster of relatively high exhaust ability or relatively low exhaust ability may be used to exhaust a required amount of dusts.
However, if the exhaust port is of large diameter, it is required that the hoses and pipes to be used in connection with the exhaust port are of so large diameter. This will extremely restrict the design and arrangement of the press body, pipes and wiring. It is, therefore, desired to make the exhaust port small.
On the other hand, if the exhaust port is small, an exhauster of relatively low exhaust ability is not sufficient a required amount of dusts. It is, therefore, required to provide another exhaust port of relatively large diameter which may be alternatively used with the small exhaust port.
Since the electric press is used in a clean room to exhaust the dusts generated in the press to the outside of the room into the open air, the electric press is not required to be completely airtight. However, a small gap or clearance of the electric press will allow a small amount of dusts to flow out through the gap when the electric press is operated while the exhauster is inoperative condition.
In the room requiring a high level of cleanliness, the electric press releasing the dusts, even if in small amount, is not desirable. Therefore, an electric press is desired, which will release no dusts even if it is operated while the exhauster is inoperative condition.
It is, therefore, an object of the invention to provide an electric press provided with a dust generation preventing device adapted to being used in a clean room.
It is another object of the invention to provide an electric press which is compact in structure and effective in operation.
It is another object of the invention to provide an electric press which may be used in combination alternatively with an exhauster of relatively high exhaust ability and an exhauster of relatively low exhaust ability in dependence upon the operation mode of the electric press.
It is still another object of the invention to provide an electric press which will not release dusts if it is operated while the exhauster is inoperative condition.
For attaining the objects, the electric press comprises a substantially airtight casing containing therein a drive device for reciprocatingly moving a ram relative to a work positioned on a base to press the work, and a device for exhausting the dusts produced within the casing from a room where the electric press is located to the outside into open air through a pipe connected to the casing, dust exhausting means including at least two openings provided at the casing thereof, one of the openings being of a relatively small diameter to be used in connection with an exhauster of a normal level of exhausting ability and the other of the openings being of a relatively large diameter to be used in connection with an exhauster of a relatively low level of exhausting ability. Further the casing is divided into an upper portion and a lower portion, and the upper portion is detachably mounted to said lower portion. The dust exhausting means includes a sealing sheet of a property preventing dusts from passing therethrough, the sealing sheet has one end secured to the inside of the upper portion of said casing such that the free end of the sealing sheet extends down into the lower portion of said casing all therearound to close a clearance between the upper portion and the lower portion, said sheet being yielding to the exhausting force of said exhauster to allow outer air to flow into said casing through the clearance when the exhauster is operated.